São José dos Campos, Brazil
São José dos Campos, Brazil

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Castro R.M.,IEAv Institute Estudos Avancados | Castro R.M.,University of Taubaté | Vanin V.R.,University of Sao Paulo | Pascholati P.R.,University of Sao Paulo | Maidana N.L.,University of Sao Paulo
AIP Conference Proceedings | Year: 2011

The intensities of weak gamma-ray transitions in the 152Sm level scheme from 152Eu decay measured in two gamma-ray coincidence experiments are compared; almost 40 new transitions with intensities around 10 -5 gamma-rays per decay and 6 new levels were observed. One of the experiments was reanalysed to confirm some findings and this new data were included in this comparison. Despite some discrepancies, the obtained decay data are in general agreement. The measured energies form a consistent data set but the intensities not, suggesting that the uncertainties are underestimated by a factor of 2. © 2011 American Institute of Physics.

Da Silveira C.R.,Federal University of Pará | Costa J.W.A.,Federal University of Pará | Giraldi M.T.R.,Military Institute of Engineering of Rio de Janeiro | Franco M.A.R.,IEAv Institute Estudos Avancados | Jorge P.A.S.,INESC Porto
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

This work presents numerical results related to an in-line Mach-Zehnder interferometer used as a refractive index sensor. The in-line Mach-Zehnder is based on abrupt tapers in standard single mode optical fiber. Numerical simulations were carried out using commercial software based on Beam Propagation Method in order to analyze the sensitivity response in terms of wavelength shift when this sensor is bent at certain radii of curvature. We realized that application of bending in the In-line Mach-Zehnder interferometer enhanced considerably the sensitivity of this sensor to the external refractive index. The best result was achieved for a radius of curvature of 10 mm (500 nm/RIU for the refractive index range of 1.33 to 1.41) improving the sensitivity about eight times in comparison with the case with no bent. © 2013 SPIE.

Pillat V.G.,University of Paraíba Valley | Pillat V.G.,National Institute for Space Research | Guimaraes L.N.F.,National Institute for Space Research | Guimaraes L.N.F.,IEAv Institute Estudos Avancados | And 2 more authors.
Computers and Geosciences | Year: 2013

The purpose of this work is to present a new computational tool for ionogram generated with a Canadian Advanced Digital Ionosonde (CADI). This new tool uses the fuzzy relation paradigm to identify the F trace and from this form extract the parameters foF2, h'F, and hpF2. The tool was very extensively tested with ionosondes that operate at low latitudes and near the equatorial region. The ionograms used in this work were recorded at São José dos Campos (23.2° S, 45.9° W; dip latitude 17.6° S) and Palmas (10.2° S, 48.2° W; dip latitude 5.5° S). These automatically extracted ionospheric parameters were compared with those obtained manually and a good agreement was found. The developed tool will greatly expedite and standardize ionogram processing. Therefore, this new tool will facilitate exchange of information among many groups that operate ionosondes of the CADI type, and will be very helpful for space weather purposes. © 2012 Elsevier Ltd.

Fogagnolo J.B.,University of Campinas | Rodrigues A.V.,University of Campinas | Lima M.S.F.,IEAv Institute Estudos Avancados | Amigo V.,Polytechnic University of Valencia | Caram R.,University of Campinas
Scripta Materialia | Year: 2013

A novel proposal is presented to increase the fatigue strength of titanium parts by applying a less rigid coating, which is expected to lower the tensile stresses at the surface and delay the onset of fatigue cracking. Niobium was introduced into the surface layer by laser surface alloying and, depending on the process parameters, β and α″ phases were obtained, resulting in a reduction of approximately 30% in Young's modulus and a more than 100% increase in hardness. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Pillat V.G.,University of Paraíba Valley | Fagundes P.R.,University of Paraíba Valley | Guimaraes L.N.F.,IEAv Institute Estudos Avancados
Journal of Atmospheric and Solar-Terrestrial Physics | Year: 2015

F-region large-scale irregularities, also called plasma bubbles, are one of the most interesting equatorial ionospheric phenomena. These irregularities are generated in the equatorial region and afterwards extend to lower latitudes. They are one of the important topics of investigation in equatorial ionosphere electrodynamics and, therefore, are subject to intense theoretical and experimental research. The ionosonde is the most used scientific equipment to study the ionosphere and the F-region. With advancement of digital ionosonde, it is now possible to carry out an ionospheric sounding with a cadence of 5. min or even with 1-minute cadence. To analyse a large amount of ionograms, more sophisticated tools are needed. Thus, development of algorithms to identify and analyse different aspects of ionograms has become very important to space science researchers. Multiple echoes recorded on ionograms are the signature of these irregularities in the ionograms, usually called Spread-F. Spread-F is classified into three types: range, frequency, and mixed. Thus, automatic identification of Spread-F is important in ionospheric studies, because studies usually involve the analysis and interpretation of large numbers of ionograms. The main objective of this paper is to present a new computational tool, based on fuzzy relation, designed to automatically identify the occurrence of Spread-F in ionograms. The test was conducted in ionograms recorded in the Brazilian sector (São José dos Campos (23.2°S, 45.9°W, dip latitude 17.6°S-low latitude) and Palmas (10.2°S, 48.2°W, dip latitude 5.5°S-near the magnetic equatorial)). The automatic identification of Spread-F occurrence was compared with those obtained manually and good agreement was found. © 2015 Elsevier Ltd.

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